Portion Of Valley Research Articles

Timing, magnitude, and style of Miocene deformation, west-central Walker Lane belt, Nevada

The timing, magnitude, style, and kinematics of deformation in the Eastern California shear zone and Walker Lane belt are important in defining interactions between shear-dominated plate-boundary tectonics and extension-dominated plate-interior tectonics. Geologic studies of middle Miocene strata in a 50-km-long north-south belt along the west margin of the Wassuk Range, west-central Walker Lane belt, reveal a pattern of folding on subhorizontal axes associated with displacements on convex-upward faults, a pattern that greatly reduces estimates of extension. We report an array of previously unrecognized shortening structures, including east-west folds, reverse faults, and steep-axis folds that formed at high angle to, and synchronous with, regional extension in the Coal Valley portion of the Walker Lane belt west of the Wassuk Range. We also report new radiometric age data and field relationships that support a reinterpretation of the history, magnitude, and distribution of extensional deformation. Instead of extreme (150%–200%) extension at 15–13 Ma, the new data support moderate (perhaps 30%) extension beginning ca. 10 Ma, coincident with the development of an inboard component of plate-boundary transtensional deformation. Also, new age data from moderately tilted pre-extension volcanic rocks forming the lower part of the Tertiary stratigraphic section in the southern Singatse Range, west of the northern Wassuk Range, show a lack of the extreme extension reported for coeval strata in the central part of that range. Published tectonic models that assume that extreme middle Miocene extension was uniformly distributed from the central Singatse Range through the Coal Valley area and southward to the Mina Deflection are invalid, as are models of 100 km of westerly extensional strain migration from the Basin and Range into the Sierra Nevada. Our reinterpretation reflects a return to a Miocene history, developed almost four decades ago, of formation of a volcanic highland, followed by sedimentation in broad basins controlled partly by east-west structures, followed in turn by extensional deformation that formed the existing ranges and basins after ca. 10 Ma. Following these early studies, the history was revised based on geologic mapping and thermochronologic studies in the Gray Hills–Wassuk Range directly north of the Coal Valley area. The published thermochronologic studies of a transect across the Wassuk Range show approximate invariance across 4 km of the central range. Previously, these data had been modeled as recording rigid, whole-block west tilting of ∼50° at ca. 15 Ma, and the approximate invariance resulted in geologically instantaneous uplift of ∼6 km. However, middle Miocene strata lack evidence for such rapid large uplift; that is, large volumes of proximal coarse clastic rocks are not found, and the strata do not exhibit a pattern of growth-fault fanning expected in the tilted fault-block model. The invariance is more consistent with arching during and following magmatism than with fault-related whole-block tilting. During main-phase extension, which began at ca. 10 Ma, the range was again flexed during uplift, similar to smaller structural blocks directly to the west. How or whether the extension-normal shortening structures we describe accommodated plate-boundary strain is not clear. Northwest-striking dextral faults are not reported in the Coal Valley area or to the northwest, so there is no clear association between the shortening structures and strain accommodation at terminations, left bends, or stepovers of such faults. We speculate that the complex heterogeneous Miocene strain of the Coal Valley area records coupling of approximately east-west regional extension with extension-normal shortening. The shortening could record midcrustal flow, possibly responding to lateral gravity gradients.

Australia’s Stock Route Network: 2. Representation of fertile landscapes

Summary The Stock Route Network (SRN) of New South Wales (NSW) and Queensland is a large-scale system of predominantly roadside remnant vegetation, which was established in the 1800s to allow livestock to be moved. Proposed changes to the management of the SRN could result in some portions of it being sold to private landholders, or subjected to long-term set-stocking. This may have potentially negative impacts on some of the values of the SRN. One key feature of the SRN is that it covers low-lying parts of the landscape, which are poorly protected by national parks. To quantify this, we specifically analysed a 41 million hectare portion of the SRN which transects the NSW ‘wheat-sheep belt’, characterising its representation of woody vegetation cover and topography, and contrasting this with the National Reserve System. Our analysis revealed that 55% of stock routes occur in low-lying valley portions of the landscape, compared with only 6% of the National Reserve System. The SRN supports a wide range of vegetation types and, unlike the National Reserve System, is not biased towards heavily forested areas. White Box-Yellow Box-Blakeley’s Red Gum woodland, which is listed as critically endangered by the Australian Government, was recorded in 803 (or 17.5%) of the 4575 stock routes in our data set. In contrast, only 10 of the 335 reserves within our spatial study region are known to support small occurrences of this community. Our findings suggest that the protection of the SRN and National Reserve System together may fulfil the ‘representation’ goal of systematic conservation planning far better than the National Reserve System on its own. Future research should quantify which stock routes in particular should receive priority for protection.

Prediction of liner wear by extending the Kragelskii model for wear of roughness peaks in sparse contact

The known wear model of Kragelskii for surfaces considers elastic loading of the normal roughness peaks in sparse contact by the shear load along the direction of sliding. Repeated stressing of the peaks causes fatigue to detach material in the form of wear debris. In this paper, an attempt is successfully made to predict the wear of cylinder liners of wide-ranging surface finishes and material strengths, by extending the model to take into account surfaces that do not have normally peaked roughness. The roughness peaks are modelled as tiny hemispheres. The radius of the hemisphere is defined as the geometric mean of the radii in the directions transverse and longitudinal to machining. The transverse radius can be estimated using the actual roughness trace. An alternative and quicker method is presented here to derive this radius as a function of the number of roughness peaks per unit length, the peak roughness, Rp k, and the fraction of the bearing surface MR 1 at Rp k. The latter radius along the machining direction is typical of the machining process. The wear rate of a normal finish is known to be a strong function of the maximum deviation of the roughness trace from the mean line, Rp. The valley portion of roughness, R vk, does not take part in wear as actively as the roughness parameter, R k, lying between Rvk and Rpk. A general surface roughness, which is not normally peaked, is characterized by the plateauness ratio, R k/ Rvk. In the present work, an equivalent roughness Rp-eq for such a general surface is found to bear a unique relation with the plateauness ratio. To study surfaces of general roughness, the equivalent Rp-eq and the radius of the hemispherical roughness peak were substituted in the wear model known for surfaces with normal roughness. Ten different liner surfaces reported in the literature were studied using the present model. In addition, experiments were conducted on a 105mm bore diesel engine using normally honed liners to apply the wear model. A satisfactory correlation was obtained between the predicted wear rates and those measured with the model. Finally, the results are discussed in the light of wear predicted by Archard [3, 11].

Comparing pocket gopher ( Thomomys bottae) density in alfalfa stands to assess management and conservation goals in northern California

Pocket gophers ( Thomomys bottae) affect alfalfa ( Medicago sativa L.) production in Yolo County, California, as well as the distribution of special status, rare species that either prey on gophers or use their burrows as habitat. Farming practices, as well as attributes of the landscape and of alfalfa fields, were compared to 134 estimates of gopher density among 35 alfalfa stands scattered throughout the County during 1992–1994. Gophers in alfalfa fields averaged only one-fourth the average density among published reports, and the range from low to high density was much smaller in alfalfa fields. Gopher density was greater at the field edge, especially during the first 2 years of stand production. Preference for the edge decreased by the third year of alfalfa production as gophers used the available space in the field interior. A stepwise multiple regression model could explain 73% of the variation in the 134 estimates of gopher density. This variation was explained by years since sowing of the alfalfa (standardized slope coefficient, β≈0.52), annual frequency of flood irrigation ( β≈−0.43), habitat area as a percentage of the landscape within a 500 m buffer around the field ( β≈0.31), season of the year ( β≈0.25), field size ( β≈−0.20) and percentage of sand within the top soil layer ( β≈0.16). This model can be used to predict the distribution of special status species that depend on gophers, and can be used to guide conservation efforts by increasing the spatial extent of non-cultivated gopher habitat on suitable areas intervening alfalfa fields. Non-cultivated gopher habitat is currently rare in the valley portion of Yolo County. Gopher control failed to influence density to the magnitude sought by the alfalfa growers, and cessation of control would benefit both production and conservation goals in some alfalfa growing regions.

PEDOGENIC AND MORPHOLOGICAL CHARACTERISTICS OF MARL-DERIVED SOILS IN THE RIDGE AND VALLEY PROVINCE, EASTERN UNITED STATES

While soils with free carbonates are rare in udic moisture regime, calcareous soils (10 to 99% CaCO 3 ) are found along drainageways in the Ridge and Valley Region (in the Great Limestone Valley portion) of the Eastern United States. These soils have developed from biogenically derived marl deposited in freshwater, ponded, settings during the late Pleistocene to the early Holocene Epochs. Pedogenesis in these marls has resulted in calcareous soils anomalous for this region; most of the adjacent upland limestone-derived soils are slightly acid and kaolinitic. Our study investigated the pedological attributes of these soils. Six transects, including four sampling pits, were examined in marl-derived map units in the Hagerstown Valley portion of the Great Limestone Valley, and chemical and physical characterization of the soils was conducted. Micro- and macromorphological investigation of carbonate forms indicated that calcic horizons were present in these soils, which is not typical in humid regions. Most of these soils possessed mollic epipedons and buried A horizons and were Mollisols. Common limnic materials in the solum were inherited from the parent material. The recent adoption of the Lma horizon designation for layers containing marl is appropriate for some of the horizons contained in these marl-derived soils.

Modelling an inland Delta aquifer system to evolve pre-development management schemes: a case study in Upper Thamalakane River valley, Botswana, southern Africa

Groundwater modelling studies have been found to be a potential tool in planning the pre-development management of groundwater resources in newly developing aquifer systems. One such study was attempted in Upper Thamalakane River valley, Okavango Delta, Botswana (southern Africa). There are three major aquifers separated by two aquitards in the valley portion. The top two aquifers are freshwater bearing zones and the bottom one is saline. The hydrological set-up of the basin is complex, as the groundwater flow directions are opposite in the upper-unconfined and in the lower-confined aquifers. A preliminary multilayer model was developed for this aquifer system by making use of only available data. The hydrodynamic behavior was then studied under two prediction scenarios to evolve appropriate management decisions for locating the well field (large diameter wells) in the upper aquifer by making use of induced river infiltration during the flood season. The aquifer response for variable river-flow conditions was studied and the induced river infiltration was quantified.

Deformation and Stress Analysis of Sealing Bellows Boots for Constant-Velocity Joints.

The main break down modes of constant velocity joints are the fatigue break at the valley portion of the bellows and the wear break caused by friction in the bellows. We measure the stress which ar the causes of break down by the photoelastic method. Maximum stress is located the surface of the valley portion of the bellows, and it's location agree that of the fatigue break. We analyzed the stress, strain and the contact pressure in the bellows by finite element method, and proved that the FEM results is accurate by comparison between experimental results and FEM results. The Ogden model which is obtained from the data of the stress and strain through the test of the strip biaxial extension is effective in the nonlinear problem of the rubber.

NUTRIENTS IN STREAMS DURING BASEFLOW IN SELECTED ENVIRONMENTAL SEVFINGS OF THE POTOMAC RiVER BASIN1

ABSTRACT: A regional assessment of water quality in small streams was conducted within four areas of distinct physiography and lithology in the upper Potomac River Basin. The Potomac River is a major tributary to the Chesapeake Bay, and this study provides new insight on the relationships between nutrient concentrations in small streams and watershed characteristics within this river basin. Nutrient concentrations were compared to land‐use data including categories for agriculture (cropland and pasture), urban areas, and forests. Among agricultural areas, streams draining areas of intense row cropping typically contained higher nitrate concentrations than did those draining pastures. Streams draining forested areas typically had the lowest nutrient concentrations. Streams in areas underlain by carbonate bedrock were more likely to contain elevated concentrations of inorganic nitrogen and potassium than did streams in areas underlain by fractured siliciclastic or crystalline rocks, and we suggest that this is a physical phenomenon related to high hydraulic conductivities in carbonate ground‐water systems. The median nitrate concentrations were highest in the Great Valley portion of the Valley and Ridge physiographic province, particularly in watersheds that have both carbonate bedrock and intensive row cropping. Values of nitrate in these streams ranged up to 8.99 mg/L as nitrogen. The soluble phosphorus concentrations during baseflow were generally low in all sub‐units, even in some settings with potential for high phosphorus inputs such as urban areas with municipal point sources or agricultural areas. The mobility of phosphorus in these environments may be hindered by adsorption and geochemical reactions.

The shoreline preservation index as a relative‐age dating tool for late pleistocene shorelines: An example from the bonneville basin, U.S.A.

AbstractThis paper evaluates the utility of the shoreline preservation index (s.p.i.) for estimating the age of late Pleistocene palaeolake shorelines, the relative influence of various factors on shoreline preservation, and whether shoreline preservation varies significantly with shoreline aspect. Sampled shorelines from the 3300 km2 study area, which includes the Skull, Tule and Puddle Valley portions of the Lake Bonneville basin, range in age from approximately 26 to 12 ka. Their total s.p.i. values range from 23 to 69 per cent, average 46 per cent, and do not vary significantly with shoreline aspect. The data from Skull and Tule Valleys, where studied shorelines are of known age, are analysed first in order to determine if there are statistically significant associations between variables representing shoreline preservation, age, degree of geomorphic development and duration of subaerial exposure. Pairwise correlation is then repeated using observations from all three valleys in order to determine how data from the Puddle Valley shorelines, whose hypothesized ages are not supported by radiocarbon analyses, affect the results. Results show that s.p.i. is useful as a relative‐age dating tool, that the postulated ages of the Puddle Valley shorelines are ordinally correct, and that geomorphic development is not an important influence on the preservation of these late Pleistocene shorelines. The relative importance of shoreline age and the relative unimportance of duration of subaerial exposure with respect to shoreline preservation suggest that subaqueous processes play a more substantial role in shoreline obliteration than is generally suggested.

Stratigraphic Architecture of the Tonganoxie Paleovalley Fill (Lower Virgilian) in Northeastern Kansas

Lower Pennsylvanian paleovalley-confined sandstones are important petroleum reservoirs in the Midwest. In Kansas, such reservoirs have produced approximately 220 million bbl of oil and 1.7 tcf of gas. Valley-fill successions tend to become muddy upward, but there can be considerable local heterogeneity in which reservoir sandstones pass laterally into muddy sandstones or nonreservoir shales. The lack of understanding of this reservoir heterogeneity can lead to low drilling success rates. The Tonganoxie paleovalley (Upper Pennsylvanian, northeastern Kansas) contains facies very similar to Lower Pennsylvanian (Morrowan) valley fills, and can provide an outcrop- and subsurface-based model of sandstone deposition. The Tonganoxie paleovalley was incised during lowered sea level and filled during the subsequent transgression. The main paleovalley is approximately 41 m deep, 11 km wide, and 240 km long, and was fed by 1-km-wide tributary valleys oriented roughly normal to the trunk valley. Sandstones occur in four distinct architectural elements that were deposited during different phases of transgression. Type I sandstone consists of a belt of sandstone and conglomerate 3-18 m thick and confined to the trunk valley and wider portions of tributary valleys. Type I sandstone consists of amalgamated channel fills, has little or no mud, and has the highest porosity and permeability. The type I sandstone is overlain by estuarine deposits of sandstone (type II sandstones), rippled argillaceous sandstone to sandy mudstone, and coal. Most of the paleovalley was filled during this stage. The type II sandstones are narrow (1.5 km wide) arcuate bodies up to 8 km long and were likely deposited in tidal point bars near the fluvial to tidal transition, are either isolated sandstone bodies or are incised into type I sandstone. The higher mud content is expected to reduce porosity and permeability compared to fluvial facies. Type III sandstone bodies occur at the upstream limits of narrow tributaries and are probably bay-head deltas. Well logs indicate a range of mud content. Type IV sandstone is a thin (3 m) discontinuous sheet of marine sandstone deposited after most of the paleovalley had been filled.

The Epidemiology and Ecology of Blastomycosis, Coccidioidomycosis and Histoplasmosis

Blastomycosis, coccidioidomycosis and histoplasmosis are the major pulmonary mycoses of humans. Each is considered to be a primary pulmonary disease acquired by inhalation of infectious spores from the environment. Blastomycosis occurs predominantly in the Mississippi River Valley and Southeastern portions of the U.S.A. Clinical cases have also been noted from a few other areas of the world. The etiologic agent, Blastomyces dermatitidis, is not readily recoverable from nature, but the disease is not contagious and must be acquired from some exogenous source poorly defined at present. Blastomycosis is common in dogs but unusual in other species although a wide variety of animals can be infected experimentally. The disease is more common in middle age, in blacks, and in males. Coccidioidomycosis is restricted to the Western Hemisphere where most cases occur in the semiarid regions of Southwestern U.S. and contiguous areas of Mexico. Limited endemic foci are found in South and Central American locations. The arthroconidia of Coccidioides immitis occur in the soil of endemic areas from whence they are inhaled by humans and other animals. The disease is not customarily contagious. Handling cultures in the laboratory is a serious biohazard. The basis for an apparent racial predisposition to develop disseminated disease is unknown. Two clinical entities distinguishable by their etiologic agents are recognized to comprise histoplasmosis. Histoplasmosis caused by Histoplasma capsulatum var. capsulatum is a cosmopolitan disease with the greatest known concentration of cases located in the eastern half of the U.S. and most of Latin America.(ABSTRACT TRUNCATED AT 250 WORDS)

Smooth groove formation method employing spin coating of negative replica of inscribed disk

A method of forming a recording disc having a smooth groove suitable for recording video information from a disc having irregularities along the peaks between adjacent groove convolutions by replicating the grooved disc to produce a negative reproduction of the groove and applying an excess of deformable or removable material such as electron beam sensitive material to the surface of the replicated disc while rotating the disc rapidly only long enough to drive off the excess material and allowing the remaining material to dry, partially filling the groove and providing a continuous coating over the wall and valley portions thereof.

A Descriptive Survey of Woody Phreatophytes along the Arkansas River in Kansas

The floodplain vegetation of the Great Plains is becoming increasingly important in relation to water salvage and flood controI. There halre been numerous investigations on floodplain vegetation in the arid and semiarid regions of Western United States, but only a few have been done on the Kansas waterways (Griswold, 1942; Tomanek and Ziegler, 1960; Goodman et dl., (1968). Some floodplain growth has been termed phreatoyphyte vegetation and it exists because of an abundant supply of subsurface moisture. The term which in Greek means well plant was initiated by Meinter (1923) and was given t{> a group of plants that send their roots down to the ground water and habitually depend upon this subsurface water supply. The primary woody phreatoyhptes in Western Kansas are cottonwcrod (Popglvs svrgerltii), salt cedar (Tama1flix ramosissim)a2 and willow (Salix spp). Phreatophytes create two problems. They cause considerable ground water loss through transpiration. Also, they interfere with the flow of flood water, resulting in deposition of sediment, thereby raising the level of the stream channel and reducing its capacity to carry flood waters (Robinson, 1958a). Robinson (l958b) estimated that in 17 Western states they cover 16 million acres and transpire about 25 million acre-feet of useful water each year. In terms of man's needs, the water used by a square mile (640 acres) of cottonwood, would supply the water demands of a city of about 23n500 population, while the demands of a city of nearly 28n300 population could be supplied by 1 square mile of salt cedar (Robinsonn 1967) . The study area incIuded about 250 miles of the Arkansas River Valley in eight Western Kansas counties. This portion of valley extended from the Colorado-Kansas stateline to 6 miles east of Great Bend in Barton County (Fig. 1). The purpose of this study was to determine the distribution, structural characteristics, and total and relative amounts of the woody phreatophyte vegetation that occurred along the Arkansas River ValIey.

VALUE OF THE LONGITUDINAL CROSS-SECTION OF A RIVER VALLEY IN ENGINEERING GEOLOGICAL PLANNING

A longitudinal topographic river section and a large-scale geological map allow the geological engineer to forecast with an accuracy sufficient for practical purposes the geological engineering conditions expected at the river valley portion under consideration. The bends of the longitudinal river section provide “guide features” of a sort in choosing the most favorable site for concrete dams. In geologically young river valleys, areas of locally increased gradient of the river are most favorable for concrete dam construction.—Auth. English summ.

Fern Collecting in Southern Costa Rica

That large section of Costa Rica which lies to the south of San Jose, its capital city, is nearly all wild, mountainous, sparsely inhabited, forested country. The backbone of the region is the non-volcanic Cordillera de Talamanca, which rises in the craggy summits of Chirripo (12,580 feet) to the most elevated point between Guatemala and Colombia. On the highest treeless summits of this range are found the northernmost outposts of the pdramo formation of the Andes; corresponding elevations in Guatemala support a vegetation far more Arctic-alpine than Andean in composition and appearance. The broken foothills of the Cordillera push down nearly or quite to the coasts, leaving at best a narrow coastal plain. Lofty, humid forests sweep up almost unbroken from the seashore nearly to the tops of the highest mountains. Although to the north of the Gulf of Nicoya the Pacific coast of Central America is nearly everywhere arid or semi-arid, in southern Costa Rica this side is almost as wet as the opposite Caribbean slope. Seven years' records from Pedregoso in the basin of El General show an annual rainfall ranging from 88 to 167 inches.1 The Pacific slopes of the Cordillera de Talamanca drain into the Rio Grande de Terraba, which flows for a long way parallel to the Cordillera. The upper portion of the Terraba Valley is the valley, or more properly basin, of El General. Aside from the pioneer explora-

Evidence of a glacial dam in the Allegheny River between Warren, Pennsylvania, and Tionesta

The observable Field Data as to upper Drainage The portion of the Allegheny River Valley between Warren, Pennsylvania, and Tionesta presents some of the most puzzling and important glacial phenomena bearing on the interval of time separating the earliest from the latest advances of glacial ice. The moraine traced by Lewis and Wright here falls several miles short of reaching the Allegheny River at Warren. But older glacial deposits are found several miles south of the Allegheny about the headwaters of Tionesta Creek, at Stoneham and Clarendon. These are evidently waterlaid, and fill a broad valley opening north into the Allegheny about two miles above Warren. The glacial deposits at Clarendon are 308 feet thick. The upper 60 feet consist of gravel containing a noticeable amount of granitic material. This is underlain by 148 feet of sand containing a small amount of gravel. Beneath this there are 100 feet of . . .

On some Postglacial Ravines in the Chalk Wolds of Lincolnshire

I n a paper recently read before this Society I pointed out that the disposition of the Boulder-clays (Purple and Hessle series) along the eastern border of the Chalk Wolds enables us to determine the relative age of the valleys which intersect the hills, and proves that some of them are older and some newer than the formation of those Clays. Most of the larger and wider valleys are occupied by deposits of glacial clay and gravel, which are continuous with the main mass or sheet of these beds lying to the eastward, and are, in fact, mere arms or prolongations of that sheet; it is clear therefore that all such valleys are of anterior date and must have existed prior to the formation of the East-Lincolnshire Boulder-clays. It would not be safe, however, to call them Preglacial, because these particular Boulder-clays are believed to be the latest glacial beds in England, and therefore the valleys may be really of Interglacial age. On the other hand such valleys or portions of valleys as can be proved to have come into existence after the formation of these Clays may safely be termed Postglacial There are several short valleys, from one to three miles in length, which open eastward on to the Boulder-clay plain, which are probably of Postglacial date ; for the boundary line of the Boulder-clay passes straight across their mouths ; no tongues of clay are thrust westward into these valleys, which are completely free from any trace of glacial

Art. XXVIII.—The Past and Present Condition of the Deyrah Dhoon

The Deyrah Dhoon, or, perhaps, more properly, Dehra Dhoon, is a valley cut off from the Dooab of the Ganges and Jumna by the Sevallic range of hills (average height about 2000 feet), which runs from the Ganges, at Hurdwar, in a north-westerly direction to the Jumna. Parallel with this range, to the north-east, is the first blue range of the Himalayas, on which Mussoorie and Landour are situated. Between these ranges, which are at an average distance from each other of about eight miles, lies the valley of the Dhoon. The bases of the hills, and a portion of the valley adjoining them, on each side, are covered with forests of very valuable timber. The centre of the valley, along its whole length, is open, with one trifling exception; and, where not cultivated, is covered with grass jungle, and a sprinkling of trees, both solitary and in clumps or belts, which, from a distance, gives the country a most park-like appearance. The town of Deyrah, and the cantonments of the Sirmoor battalion, stand in the middle of the valley, where it is intersected in its length by a road from the Ganges to the Jumna, and in its breadth by another from the plains of Indus, (through the Sevallic range,) to the Sanatorium of Mussoorie and Landour. The latter is fourteen miles from Deyrah, (half of which is ascent, the depôt being about 6300 feet above the valley,) and 7500 feet above the level of the sea. The water-shed, called here “pani dal,” also is near Deyrah, and streams rising on the one side of it run to the Ganges, on the other to the Jumna. These streams are large, increasing as they get nearer to the great rivers; very pure and clear; and, being of considerable rapidity, are well calculated to turn machinery, or to be turned out of their channels to irrigate the country as they pass.